In this article, we describe twopm, a command for fitting two-part models for mixed discrete-continuous outcomes. In the two-part model, a binary choice model is fit for the probability of observing a positive-versus-zero outcome. Then, conditional on a positive outcome, an appropriate...

In this article, we explain how to calculate adjusted risk ratios and risk differences when reporting results from logit, probit, and related nonlinear models. Building on Stata’s margins command, we create a new postestimation command, adjrr, that calculates adjusted risk ratios and adjusted...

This paper explains why computing the marginal effect of a change in two variables is more complicated in nonlinear models than in linear models. The command inteff computes the correct marginal effect of a change in two interacted variables for a logit or probit model, as well as the correct...